<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script src="js/jquery-3.4.1.js" type="text/javascript" charset="utf-8"></script>
		<script type="text/javascript">
			$(function(){
				// 功能 : 将ul下面子元素颜色改变
				// 原来方式: $("ul li").css("color", "red");
				$("ul").children().css("color","red")
				
				// children配合过滤选择器使用
				$("ul").children(":first").css("background-color","yellow")
				$("ul").children(":gt(0)").css("background-color","blue")
				
				// find 配合选择器使用
				$("ul").find("span").css("background-color","green")
			})
		</script>
	</head>
	<body>
		<ul>
			<li>li111</li>
			<li>li222</li>
			<li>li333</li>
			<li><span>li444</span></li>
		</ul>
	</body>
</html>
